CMT: Prelims

Role of Experimentation and Testing

1. Development

2. Quality Control

3. Scientific Measurement

4. Education

Development

Drives the development of new materials and devices by validating whether an innovation performs as intended

Quality Control

controls the quality of materials during production and construction, confirming they meet required standards

Scientific Measurement

provides objective, repeatable scientific measurement of material behavior under controlled conditions

Education

gives substance to theoretical concepts and reinforces insights gained from analytical studies

Significance of Test

1. Directly usable in design

2. Proven by experience

Directly usable in design

the test adequately measures a property that is significantly basic and representative - its results can be used directly in design calculations

Proven by experience

even if the procedure is highly arbitrary, the test reliably identifies materials that experience has shown to give satisfactory performance

Destructive Testing

the specimen is loaded, altered, or fractured to establish its properties

• specimen is permanently damaged or consumed

• yields direct, quantitative strength & failure data

• e.g. compression, tension, and flexure tests

Non-Destructive Testing

the specimen’s properties are evaluated without impairing its future usefulness

• specimen remains intact and serviceable

• used for field inspection and in-service monitoring

• e.g. rebound hammer, ultrasonic pulse velocity

Principal Objectives in Testing

1. Research

2. Quality Control

3. Service Evaluation

Research

explores the fundamental nature and behavior of materials to expand engineering knowledge and inform new theory

Quality Control

verifies that a material or product conforms to specification before acceptance, use, or release for construction

Service Evaluation

Assess how a material or structure performs under actual or simulated performs under actual or simulated service conditions to judge suitability and durability

Errors in Testing

1. Systematic Errors

2. Random Errors

3. Gross Errors

Systematic Errors

consistent, repeatable deviations caused by instrument calibration, technique, or environmental bias — they skew results in one direction

Random Errors

unpredictable fluctuations from uncontrollable variables (minor vibration, reading vibration) that scatter results around the true value

Gross Errors

blunders from human mistakes — misreading a scale, faulty setup, or data transcription errors — which should be identified and discarded

Accuracy

the closeness of a measured value to the true or accepted value of the property being tested

Precision

the closeness of agreement among repeated measurements of the same quantity, regardless of whether they are correct

Balance

determines the mass of specimens with precision; sensitivity varies from 0.1 g to 0.01 g depending on the test

Scoop / Shovel

used to transfer bulk aggregate, cement, or soil samples into containers or testing molds

Squeeze Bottle

dispenses controlled, small amounts of water of liquid reagent during sample preparation

Tamping Rod

a steel rod used to compact soil, concrete, or aggregate samples uniformly within a mold

Graduated Cylinder

measures the volume of liquids used in specific gravity, consistency, and mix-water determinations

Air-Tight Container

preserves the natural moisture content of a soil or material sample between sampling and testing.

Moisture Cas

small metal containers used to hold specimens during oven-drying for moisture content determination

Controlled / Humidity Oven

dries or conditions specimens at a fixed temperature and humidity for standardized test preparation

Warm Air Dryer

provides rapid, gently drying of moisture-sensitive samples without damaging their structure

Tray

A flat stainless container used for mixing, cooling, or holding prepared specimens

Glass Plate

a flat, non-reactive surface used for spreading, mixing, or observing paste and fine material samples

Result of Agreement

a standard specification for a material is usually the result of agreement among those concerned in the particular field, and involves acceptance for use by participating agencies

Continuously Revised

standard specifications are continuously revised as technical advances are made, keeping requirements aligned with current knowledge and practice

AASHTO

American Association of State Highway and Transportation Officials

ASTM

American Society for Testing and Materials

AASHTO

• develops standard methods for testing materials

• sets up standard definitions of terms

• gives standard formulation of material specifications

• formulates recommended practices for the utilization of materials

Classes of Material Properties

• General

• Chemical

• Physicochemical

• Mechanical

• Thermal

• Electrical & Magnetic

• Acoustical

• Optical

General Properties

• Density & Unit Weight

• Porosity

• Durability

• Appearance and Finish

• Wear Resistance

• Cost & Availability

Chemical Properties

• oxide or compound composition

• acidity or alkalinity

• resistance to corrosion or weathering

Physicochemical Properties

• water-absorptive or water-repellent action

• shrinkage and swell dude to moisture change

Mechanical Properties

• strength

• elasticity / plasticity

• hardness and wear resistance

• stiffness

• ductility / brittleness

Strength

tension, compression, shear & flexure

state, impact & endurance loading

Elasticity / Plasticity

ability to recover shape vs deform permanently

Hardness and Wear Resistance

Resistance to indentation, scratching & abrasion

Stiffness

resistance to elastic deformation under load

Ductility / Brittleness

capacity for plastic deformation before fracture

Thermal conductivity

rate of heat transfer through the material

Thermal expansion

dimensional change with temperature

Specific Heat

heat enegry required to raise temperature

Fire resistance

behavior and performance under high heat

Electrical and Magnetic Properties

• Conductivity

• Magnetic permeability

• Galvanic action

Acoustical Properties

• Sound transmission

• Sound reflection

Optical Properties of Engineering Materials

• Color

• Light transmission

• Light reflection

Mechanical Requirements

the strength, stiffness, and ductility demanded by the design loads and intended function of the element

Durability and Service Life

expanded resistance to weathering, wear, and chemical exposure across the structure’s design life

Cost

material, fabrication, transportation, and lifecycle maintenance costs weighed against the project budget

Availability and Supply

Local sourcing, lead times, and consistency of supply for the required quantity and quality

Environmental Impact

embodied carbon, recyclability, and sustainability of sourcing and disposal across the material’s lifecycle

Aesthetics and Finish

appearance, texture, and architectural intent for elements that remain exposed to view

Manufacturability

ease of fabrication, forming, jointing, and installation with available skills and equipment

Codes and Standards

Compliance with applicable building codes, standard specifications, and regulatory requirements

Physical Properties

the measurable characteristics that describe a material’s composition and physical state — the starting point for evaluating any construction material

Bulk density

• the mass of a unit volume of material in its natural state, including internal pores and voids.

• For most solids, bulk density is lower than true density; for liquids, glass, and dense stone it is practically the
  same. This strongly influences strength and heat conductivity

Bulk density

ρb = m / v

Porosity

• the percentage of a material's total volume that is occupied by pores and voids.

• It is the complement of the density index and is one of the most influential properties governing strength,
  thermal insulation, water absorption, and durability

Porosity

P = (1 - ρo) x 100%

Specific Gravity

a dimensionless quantity defined as the ratio of the density of a substance to the density of water at a specified temperature (commonly 4°C, where water is at its densest).

Specific Gravity

SG = ρ material / ρ water

Mechanical Properties

How a material responds to applied forces — its capacity to carry load, deform, and resist failure defines its structural role.

Strength

• a material's ability to resist an applied load without rupture or excessive deformation.

• it is quantified as stress — the internal force distributed over the cross-sectional area that resists the
  load

Strength

σ = P / A

Elasticity

• Ability to return to its original shape once the load is removed.

• Governed by the modulus of elasticity, E = stress / strain (Hooke's Law).

Plasticity

Tendency to retain a permanent, non-recoverable deformation after the load exceeds the material's elastic limit

Ductility

Ability to undergo large plastic (tensile) deformation before fracture — e.g., mild steel, copper

Brittleness

Fractures with little or no plastic deformation — e.g., glass, cast iron, unreinforced concrete

Toughness

Total energy a material can absorb before fracture; represented by the area under the stress-strain curve.

Hardness

Resistance of a surface to indentation, scratching, or abrasion — measured on Rockwell, Brinell, or Mohs scales.

Material Testing Methods

Standardized laboratory procedures used to verify that a material meets
the strength, durability, and quality required for construction

Compression Test

What test is Compressive Strength

Tension (Tensile) Test

what test is Tensile strength and modulus of elasticity

Slump Test

what test is Workability / Consistency of fresh concrete

Water Absorption Test

what test is Porosity and durability

Los Angeles Abrasion Test

What test is Hardness and toughness of coarse aggregate

Charpy Impact Test

What test is Toughness / Impact Resistance